Mobile equipment networks provide real-time wireless communication services to subscriber communication terminals, through a planned deployment of radio access base stations. Base stations are carefully positioned throughout the deployment to provide seamless wireless coverage for a geographic area served by a mobile equipment network. Because gaps in base station coverage result in communication dead spots, or areas without wireless service, network operators tend to carefully test base station deployments to identify and correct gaps in wireless coverage.
Because base station deployments are carefully planned to provide seamless wireless coverage, respective geographic locations of individual base stations are generally well known by service providers. Some providers store base station location data in a network server, and leverage this data to provide communication services. For instance, knowledge of base station position can be useful in assisting subscriber terminal position applications including, for example, real-time mapping software, or the like. By analyzing timing of signals transmitted to and received from a subscriber terminal, a base station can form an estimate of distance to the terminal. Multiple base stations performing similar computations can yield a position of the terminal, generally within several hundred meters accuracy. The degree of accuracy for such techniques, referred to as trilateration or multilateration more generally, can depend in part on spacing between nearby base stations, as well as various time-varying signal characteristics. In addition to the foregoing, maintenance personnel may also reference a network server that stores base station location data for identifying and locating base stations experiencing technical problems.
Mobile network systems are typically configured to identify occurrences of dropped calls, also referred to as radio interface failures. A dropped call is a circumstance where a wireless call in progress is unexpectedly terminated. Generally, the dropped call is a result of a technical problem in maintaining a radio communication interface between a subscriber terminal and a radio access network (RAN), the network of base stations acting as a radio access interface to a communication network. These technical problems can vary, but can include entering a dead zone (where base station signals cannot be received by the subscriber terminal) or otherwise moving out of range of the RAN, interference or jamming by other radio frequency transmitters, failed handoff between one base station and another, nearby base stations reaching or exceeding terminal load capacity, hardware transmission or reception problems, and so on. In rare instances, solar events such as sun spots and solar flares can affect electromagnetic fields on the Earth, leading to localized instances of dropped calls (albeit sometimes in large localities). Generally speaking, frequency of dropped calls is a common subscriber complaint for wireless service providers. Accordingly, research and development within the wireless communications industry continues to search for cost effective ways to improve wireless coverage, limit interference, improve handoff and other mobility services, and generally reduce instances of dropped calls.
Mobile network systems have some capacity to identify and track network-based communication errors. For instance, if a particular base site goes offline, network maintenance equipment can detect such an event and issue an error ticket to maintenance personnel. The maintenance personnel can use the ticket to identify the base station and its location to deploy repair resources. Networks can often identify particular base stations experiencing a high dropped call rate, as well. However, a high dropped call rate itself does not determine exactly where the calls are dropping (with geographic resolution any better than the location of a network cell, which can be quite large) or why. Accordingly, repair tickets are issued against a base station site generally, with little additional information to locate or identify a cause of the underlying problem. Given tight resource constraints it can be impractical to expect service personnel to do extensive drive testing to locate and diagnose the problem. Thus, problems often go unresolved. Worse still, in certain mobile networks call processing occurs with soft handoff in which several base stations maintain communications with individual subscriber units concurrently. If a particular base station experiences a high dropped call rate, at least some of the other base stations may participate in the problem, expanding the potential range of the problem and further clouding its source.